This invention relates generally to the field of draw-type snorkels, and adds to pre-existing art an electrically powered diver-borne compressor that can be used to supply air to a free-swimming diver.
The prior art of interest to the present invention dates back more than a century. In U.S. Pat. No. 0,156,599, issued in 1874, Schmitz taught a breathing aid for a shallowly submerged diver. His device had inlet and outlet breathing tubes running to a diver from a surface float. A more recent teaching in the same area is provided by one of the present inventors in his application Ser. No. 07/790,530, the disclosure of which is herein incorporated by reference.
The maximum inspiration pressure that a diver can supply severely limits the utility of equipment such as that provided by Schmitz. Schmitz's device could not be used when the diver's chest was submerged more than about 30-40 cm.
Numerous devices have employed a compressor mounted above the surface of the water to supply air to a diver. Shipboard-mounted, manually-actuated compressors have been used for over a century to supply air to a "hardhat" diver. A compressor mounted on a smaller floation means than a boat or ship, i.e. an automobile inner tube, and powered by a small internal combustion engine is also known in the art for supplying air to free-swimming divers. Mitchell, in U.S. Pat. No. 4,674,493, improves on this art with a battery-powered compressor mounted on a surface float that can be towed behind a free-swimming diver. Kroling, in U.S. Pat. No. 4,472,082, teaches a manually-operable compressor mounted on a surface float. Kroling's compressor is operated by cables pulled by the diver.
There are also prior art compressors intended to be carried below the surface by a diver:
Houston, in U.S. Pat. No. 4,245,632, teaches an underwater breathing apparatus that includes two positive displacement compressors carried by the diver. One of Houston's compressors is operated by the diver's exhalations; the other is operated by hand.
Vautin, in U.S. Pat. No. 3,050,055 teaches a diver-mounted apparatus including two piston-type compressors and an air tank. The compressors are actuated by the diver's swimming motions. An improved diver-powered breathing apparatus of this sort is taught by Tragatschnig in U.S. Pat. No. 5,092,327, the teaching of which is herein incorporated by reference. Tragatschnig's apparatus is sold under the name "DIVEMAN", and is distributed in the United States by DIVEMAN America of Clearwater, Fl.
Gross, in U.S. Pat. No. 3,124,131, teaches an electrically-powered compressor on a diver's backpack. Gross' apparatus is configured for a diver who walks generally upright on the bottom of a body of water. Gross' unusual air compressor comprises an air and water mixing apparatus (of a sort originally developed for sewage treatment) that bubbles breathable air through water in a pre-inspiration chamber that has an open bottom. Gross' apparatus is of no value to a free-swimming diver, as free-swimming divers adopt a head-down attitude when submerging. This would cause Gross' apparatus to deliver water into the breathing tube.